(CNN) -- Federal authorities have identified a suspect in the armed robberies of 10 banks in four states, crediting surveillance photos they posted on electronic billboards throughout the South.

The FBI says this surveillance image shows Chad Schaffner, who they say robbed at least 10 banks this year.

Chad E. Schaffner, who was released from Indiana's prison system last year following an armed robbery conviction, was identified as the man on the billboards, making him a suspect in the robberies in Kentucky, North Carolina, South Carolina and Tennessee, the FBI said Thursday.

Schaffner may have been in the Morristown, Tennessee, area this week, according to a criminal complaint filed in federal court. A woman believed to have had a brief relationship with him alleges he was in her Morristown-area apartment and threatened to kill her children if she told authorities he was there, an FBI special agent says in the complaint.

The FBI posted photos of the robberies, occurring from May to last week, on electronic billboards in eight Southern states, in part because the robber made no apparent attempt to cover his face. Surveillance images showed a man with tattooed arms, close-cropped hair and a goatee pointing a pistol.

The FBI posted the images as part of a partnership with owners of electronic billboards.

"This case is an emblematic example of the importance of public/private sector alliances in bringing criminals to justice in today's information age," Richard Lambert, special agent in charge of the FBI's Knoxville, Tennessee, division, said in a news release Thursday.

No one was hurt in the robberies, but Schaffner, who turns 37 on Monday, should be considered armed and dangerous, the FBI said.

Don't Miss

"This guy has made no effort to hide the gun," FBI agent Kevin Keithley said earlier this week, before Schaffner was named a suspect. "He has threatened the use of it in every bank robbery he has committed. He has put the gun in the faces of tellers, threatened to use the gun against them."

Schaffner is white and about 6 feet tall, weighs 200 pounds, and has brown hair, brown eyes and tattoos on his forearms, the FBI said. He may be driving a black 1994 GMC Jimmy pickup truck with Tennessee license plate 360 WLN or a red 1994 Chevrolet S10 pickup with South Carolina license plate EVE 177, according to the FBI.

Anyone with information on his whereabouts should call the FBI or local law enforcement, the FBI said.

The last two bank robberies happened in Morristown and Jefferson City, Tennessee, on August 18. On Tuesday -- a day after the billboards started showing images of the robberies -- a man told the FBI that Schaffner was in the Morristown area at the time of the last two holdups, according to the complaint filed in court.

The man said he'd known Schaffner for about two months, the complaint says.

FBI agents also twice interviewed the Morristown-area woman this week, having heard she'd had a two-week relationship with Schaffner, according to the complaint. During the first interview, she told agents outside her apartment that she didn't know him, the complaint says.

The next day, she told authorities that she did know Schaffner, and that he had been in her apartment with her children while she talked with the agents outside, the complaint says. She said he threatened to kill the children if she told the agents about him, according to the complaint.

She told authorities that after the agents left, Schaffner left the area in a vehicle, according to the complaint.

A warrant was issued Thursday for Schaffner's arrest. He has been charged in U.S. District Court in Tennessee's eastern district with two counts of bank robbery and two counts of use of a firearm during a bank robbery.

Schaffner was released from an Indiana prison in December, the FBI said. He was convicted of armed robbery in Indianapolis, Indiana, and sentenced in June 2008.

He has several other convictions in Indiana, including for burglary, armed robbery, resisting law enforcement and purchase of a handgun without a license, according to the Indiana Department of Correction.